I've finally been able to reproduce the issue after upgrading my main system to Debian wheezy (using Spatialite 3). This has nothing to do with spatial_ref_sys data in Spatialite, but rather a consequence of the way the gdal.SpatialReference is initialized with a pseudo srs WKT.

I've uploaded a modified version of Claude's patch that works for me (spatialite 3.x here, note how the version conditional was changed to only in version 4.x otherwise most of the GIS tests fail becuase AFAICS libspatialite 3 doesn't create the new srtex column).